This invention relates generally to the extracting of coffee and black tea and more particularly to apparatus for extracting a ground powdered coffee and fine leaves of black tea in water at room temperature.
Conventional extracting apparatus for extracting a drink of coffee or tea from a ground powder of coffee and fine leaves of black tea at low temperatures are known. Generally the extraction is carried out in an open condition such that various factors effecting the loss of flavor, transparency of the filtrate and fragrance of the coffee and black tea drink occur. Heretofore these unfavorable causes of loss of flavor etc. have not been dealt with by the known extractors.
An investigation by the applicant of known extraction apparatus for coffee and tea as to the construction of the filter, the filtering process, the relationship between flow-down quality and flow-down speed of extracted solutions, the influence of oxidation (deterioration of flavor), has been carried out. Furthermore the ingress of bacteria floating in open air resulting from the exposure of the coffee and black tea during their extraction effecting a loss of flavor and change in quality (unfavorable preservation), the stirring processes and stirring apparatus etc. have been such that unfavorable results occur. That is to say these various factors have resulted in production of coffee or tea that does not have the optimum flavor and cannot be stored for long periods.